1. Technical Field
The present invention relates to an apparatus for inflating an inflatable vehicle occupant protection device. In particular, the present invention relates to an inflator for inflating an air bag to help protect a passenger of a vehicle.
2. Description of the Prior Art
U.S. Pat. No. 5,257,817 describes an air bag inflator having a flow control device. The flow control device includes a ball piston disposed in a cylinder. The ball piston has a surface against which gas under pressure from a chamber acts to move the ball piston in a first direction in the cylinder to allow increased flow of gas through a gas outlet opening. An elastomeric member controls movement of the ball piston in the cylinder.
U.S. Pat. No. 5,195,777 also describes an air bag inflator having a flow control device. The flow control device includes a piston disposed in a cylinder. The piston has a surface against which gas under pressure from a chamber acts to move the ball piston in a first direction in the cylinder to allow increased flow of gas through a gas outlet opening. A crushable honeycomb controls movement of the ball piston in the cylinder.
In the inflators described in U.S. Pat. Nos. 5,257,817 and 5,195,777, a burst disc initially blocks fluid flow from the chamber. The burst disc is opened by an increase in pressure in the chamber. The pressure increase in the chamber is caused by ignition of an ignitable material in the chamber to heat gas in the chamber to increase the pressure in the chamber.